Are these blocks more valuable than standard blocks? I've got a 3970010, 2-bolt block with the 010 under the timing cover. I know this indicates a higher nickel content, but I'm not sure if that is actually worth anything. This is a 350, not the super-duper DZ302 block. I'm not sure I want to keep the car it came in, so does it make sense to find a cheaper block to put in it and keep this one for a future project?

These are good blocks and worth keeping. However, of all the 350`s made from the ones made here with no tin or nickel, or the ones made in mexico, canada, etc. You won`t get anymore power from one block or the other if the machine work and the build is done correctly. There is a demand for the heavy duty 4 bolt blocks by roundy round racers around here but they don`t care what casting number they are. I myself prefer the 880 castings.

Are these blocks more valuable than standard blocks? I've got a 3970010, 2-bolt block with the 010 under the timing cover. I know this indicates a higher nickel content, but I'm not sure if that is actually worth anything. This is a 350, not the super-duper DZ302 block. I'm not sure I want to keep the car it came in, so does it make sense to find a cheaper block to put in it and keep this one for a future project?

thanks

stu...

Confusion between the indicators for the casting alloy and the casting number.

Numbers under the timing cover or inside the bell housing area at the rear that show 010 or 020 indicate the alloy of tin and or nickel with the iron. 010 by itself means .1% tin has been added most if not all blocks have this. 020 along with 010 indicates .2 percent nickel has been added as well as .1% tin. Tin helps the iron flow out in the mold insuring the proper amount of metal is in the right places, one could say it adds strength by insuring the proper mass is in place. Nickel adds strength by its presence as an alloying agent, nickel is a major constituent in stainless steel so you can see it adds considerable toughness to iron or steel when used in small quantities.

010 as a casting number i.e. 3970010 is found both on the outside left rear of the bell housing boss as the complete casting number and as the number "010" cast into the right side of the block ahead of the starter location. Casting number 3970010 is a very desireable block it is a 4 inch bore used for late 327s, Z28 302s, and heavy duty 350s used as performance, truck, and industrial engines. They all vary as to being 2 or 4 bolt mains. The 2 bolt blocks can be converted to 4 bolts with all the strength of factory 4 bolt versions. These are very frequently found as 350's in half ton pickups and always in 3/4 and 1 ton trucks with 4 bolt mains so there's bunches of them out there.

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